The present disclosure relates to a blanket to be used in formation of a layer to be patterned such as, for example, an organic layer of an organic electro luminescence (EL) display unit, a printing process using the blanket, and a method of manufacturing each of a display unit and an electronic apparatus.
Recently, reduction in material usage and size reduction and simplification of manufacturing equipment have been considered in response to demands for cost reduction and area increase of an electronic apparatus. Pattern formation of various functional electronic materials (for example, a conductor, a phosphor, a dielectric, and the like) using various printing processes is therefore noticed. Examples of the printing processes may include spin coating, a discharge-type printing process such as inkjet printing, flexo printing, and plate printing such as reverse offset printing.
In the plate printing, for example, an ink coating (ink layer) is formed on an intermediate transfer body called blanket. Subsequently, the ink layer is made into contact with a letterpress plate, and a pattern left on the blanket is transferred from the blanket to a printing substrate to perform printing (for example, see Japanese Unexamined Patent Application Publication No. 2000-289320).
However, since the blanket is formed of silicone rubber or the like, its wettability is low; hence, the ink layer easily becomes uneven in thickness. To cope with this, a method of forming a uniform ink layer without unevenness in thickness has been disclosed, in which an organic solvent is used as a solvent of an ink solution, the organic solvent having a surface free energy lower than a coated surface of a blanket, i.e., silicone rubber, or a surfactant is added to form such a uniform ink layer (for example, see Japanese Unexamined Patent Application Publication Nos. 2003-17261, 2005-175061, and 2005-128346).
A soft material such as silicone rubber easily absorbs an organic solvent. Hence, the ink layer applied on the blanket is easily dried into a film, thereby pattern accuracy is reduced, or patterning becomes difficult. To cope with this, for example, a method of preventing drying of the ink layer has been disclosed, in which a blanket is beforehand immersed in a predetermined organic solvent so as to be swollen before ink is applied onto the blanket (for example, see Japanese Unexamined Patent Application Publication No. 2007-160514). Alternatively, a method of forming an ink layer has been disclosed, in which an ink-coated surface of a blanket is plasma-treated so as to be hydrophilic, and an aqueous ink that is less absorbable by the silicone rubber is used to form the ink layer (for example, see Japanese Unexamined Patent Application Publication No. 2007-95517).